This invention relates to monoclonal antibodies, to diagnostic methods employing monoclonal antibodies, and to the detection of activated B-cells.
B-lymphocytes are involved in the humoral, or circulating, immune response to the extracellular phases of bacterial and viral infection. When activated by exposure to specific antigenic or mitogenic stimuli, human B-lymphocytes proliferate and subsequently differentiate into antibody secreting cells. During the stages of activation, B-cells increase in size, synthesize both DNA and RNA, and undergo changes in cell surface structures. Neoplastic changes in B-cells, e.g., leukemias or lymphomas of B-cell origin, also induce changes in the expression of cell surface antigens.
Thorley-Lawson et al., (1982) Cell 30:415-425 describe a B-cell restricted antigen (B-LAST-1) which appears on the surface of B-lymphocytes 2-3 days after stimulation with mitogens or Epstein-Barr Virus (EBV). B-LAST-1 is a single chain polypeptide with a molecular weight of 45 kd. B-LAST-1 is also found on chronic lymphocytic leukemia (CLL) cells and poorly differentiated lymphoma cells. The isotype of anti-B-LAST-1 monoclonal antibody of murine origin was reported to be IgG2b.
Yokochi et al., (1982) J. Immunol. 128:823-827 report a B-cell antigen, BB-1, which appears on the surface of EBV and mitogen-activated human and some non-human primate B-cells. The molecular weight of the BB-1 antigen is 37,000. Expression was detected 4-5 days post-EBV-activation and peaked at 7 days. BB-1 was also found on 50% of the myelomas tested.